Temperature indicating and control mechanism



July 2, 1935. F. A. HUTCHINSON 2,006;767

TEMPERATURE INDICATING AND CONTROL MECHANISM I Filed A ril 20, 1954 K3 M r.

Patented July 2, 1935 I g 2 UNITED STATES PATENT OFFICE TENIPERATURE INDICATING AND CONTROL MECHANISM Francis A. Hutchinson, Orillia, Ontario, Canada, assignor to Tudhope Meta-l Specialties Limited, Orillia, Ontario, Canada Application April 20, 1934, Serial No. 721,450 In Canada September 11, 1933 10 Claims. (01. 200138) This invention relates to thermostatically con- [6 and the adjustable back stop ll of known trolled mechanism for use with electric heating type. The fixed contact and back stop are inapparatus to switch aheating element on or off as sulated from the slide 8 by means of a block I8 may be required to attain and maintain a predeand a sheet l 8 of insulation. termined temperature in the apparatus, and my ID is a U-shaped spring frame which, by means 5 object is to devise mechanism of this character of a lug I0 is secured to the regulator frame, which will be cheap, simple and reliable. but is insulated therefrom by the block of in- I attain my object by means of a construction sulation I9. 20 is a toggle member having a of the mechanism which may be briefly described knife-edge fulcrum on the lower arm "l of the as follows. On an adjustable regulator is mount- U-shaped spring frame I0. 9 is a contact arm, 10 ed a slide carrying a fixed contact included in the the upper end of which is adapted to play beheating circuit. A movable contact, also included tween the fixed contact l6 and the back stop ll. in the heating circuit, is mounted on the regulator The upper part of this arm extends through an and is provided with snap over mechanism tendopening in the arm Ill of the frame [0, but its ing to hold the movable contact in engagement lower end 2| is of greater width than the upper with either the fixed contact or a back stop. end and. has a knife-edge fulcrum against the A thermostatically actuated indicator is prolower side of the arm I0 and a similar fulcrum vided and means whereby the indicator moves against the upper end of the toggle member the slide one way or the other to make or break which has the knife-edge fulcrum on the upper the heating circuit according as the temperature side of the lower arm Ifl of the frame I0. 20 is falling or rising. The frame I0 maintains a spring tension The invention is hereinafter more specifically against the lower end of the toggle member 20 in described and is illustrated in the accompanythe direction of its length and the various fulcra ing drawing in which are so arranged that a snapover action is obi Fig. 1 is a front elevation of mechanism contained as the contact arm 9 plays between the structed in accordance with my invention; fixed contact l6 and the back stop ll.

Fig. 2 is a side elevation, partly in section, 23 is a lead connected to the binding post 23 thereof; on the block of insulation I9 and 23 is a lead Fig. 3aplan view; I connecting the post with the fixed contact l6. Fig. 4; a section on line 4-4 in Fig. 2; and The other end of the lead 23 is connected to the Fig. 5 a section on line 5-5 in Fig. 4. terminal 24 through which connection is made In the drawing like numerals of reference inwith the circuit to be controlled. dicate corresponding parts in the different fig- A lead 25 is secured to the frame II! which is ures. electrically connected with the movable contact 5 Referring to the drawing, I2 is a support, arm 9. The other end of this lead is connected 85 which may, for example. be the rear wall of a with the terminal 26 for connection with the circasing which is adapted to be secured to a wall u o be Contr of an electrically heated oven. Supported on The ac p is carried 011 a ack t and this part I! is a thermostatic element I3 of t e fi C t Carried y a Second ac known type which needs no detailed description. et, each of these brackets is secured to the sheet 40 To the movable part l3 of this thermostatic of insulation w in spaced relationship to one anelement is secured the indicator arm I. This other- 1151s evident then thahby v ng t S de indicator arm I plays over the scale 14 secured 8 in one direction or the other, the contact arm 9 to the support l2. The scale will usually be caliwill snap o One Side e ot 0 make break 5 brated in degrees of temperature. 3 is the regua circuit through the leads 23, 23 and 25.

lator frame, which is pivoted at 2 concentric The following mechanism is provided for so with the axis of the thermostatic element on a moving the slide. The latter is provided with a bridge '4! secured to the support l2. This regutang 21 which projects through a slot in the reglator frame is provided with a regulator arm 4, ulato frame 3 and is a p d 150 be engaged y l which also plays over the scale l4 and is pro- 3- projection 6 fo med on an arm I. This arm vided with the usual pointer. On the regulator is journalledi on the part l3 beside the indicator frame is mounted the slide 8 which is provided arm I and means are provided so that the arm with screw and slot guides l5 of known type. I" will move with the arm I to cause the slide to This slide moves transversely of the length of Separate the contacts and hold them separated i the regulator arm 4 and carries the fixed contact without preventing the arm I from moving past the tang 21 if the temperature of the oven should continue to rise before it drops. This means comprises a lug I b on the arm I a and a spring I having its opposite ends connected with the arm I and with a lateral extension I on the arm I. The spring normally holds the lug I in contact with the left side of thearm I when the arm I is moved clockwise on a rise in temperature so that the arm I may continue this movement after the arm I is prevented, by means of the projection 6, tang 21, slide 8 and slot guides I5, from continuing with the arm I. With this arrangement the thermostatic element is free to expand until the temperature of the oven drops and the only extra strain applied to the element is the tensioning of the spring I. The slide 8 is constantly urged toward its position for establishing connection between the fixed contact I6 and the contact arm 9 by means of a flat spring 29 having one end secured to the regulator and the other end engaging the block of insulation l8 on the slide 8.

With the parts in the position shown in Fig. 1, the operation is as follows: The indicator arm I moves to the right as the temperature rises and the spring I causes the arm I to move with the arm I whereby the projection G engages the tang 21 and moves it and thus the slide 8 to the right. This movement of the parts l 6, 21 and 8 is limited by the screw and slot guides I5. The fixed contact thus moves the upper end of the contact arm 9 to the right until the snap-over mechanism comes into action and snaps the contact arm over so that the contact arm 9 engages the back stop H. The circuit is then broken and remains broken until the thermostatic element moves the indicator arm I back to the left. It then, if it has moved farther than the arm I, engages the lug l thereon and moves the arm I with it so that the spring 29 is permitted to' move the slide 8 to the left and thus effect a reversal of the position of the movable contact arm 9. arm as the temperature rises or falls serves to make or break the circuit which it is desired to control.

From the above description it will be seen that the device is simple in construction, can be cheaply made and will be durable and reliable in action.

What I claim as my invention is:

1. Temperature indicating and control mechanism comprising a thermostatically actuated indicator; a regulator movable relative to the indicator; circuit opening and closing means comprising a slide guided on the regulator to move relative thereto; a fixed contact carried by the slide, a snap-over actuated contact carried by the regulator and movable relative thereto into and out of engagement with the fixed contact; and means operable by the indicator for moving the movable slide to cause the snap-over actuated contact to make or break a circuit in which the contacts are included. 7

2. Mechanism as set forth in claim 1 in which the slide moving means comprises a tang on the slide, a spring tending to move the slide in one direction to cause the contacts to make the circuit, and a projection movable by the indicator adapted to engage the tang to move the slide in the opposite direction to break the circuit.

3. Temperature indicating and control mechanism comprising a pivotally mounted thermostatically actuated indicator; a regulator pivotally mounted concentric with the indicator; cir- Thus the movement of the indicator cuit opening and closing means comprising a slide guided on the regulator to move relative thereto, a fixed contact carried by the slide; a snap-over actuated contact carried by the regulator and movable relative thereto into and out of engagement with the fixed contact; and means operable by the indicator for moving the movable slide to cause the snap-over actuated contact to make or break a circuit in which the contacts are included. 1

4. Temperature indicating and control mechanism comprising a thermostatically actuated indicator; a regulator movable relative to the indicator; circuit opening and closing means comprising a slide movable on the regulator and car- 1 rying a fixed contact, a snap-over actuated contact movable on the regulator and including a contact arm pivoted intermediate of its ends and adapted at one end to engage the fixed contact, a back stop for the contact arm, a toggle member at one end pivotally engaging the other end of the contact arm, means for applying spring pressure to the other end of the toggle member in the direction of its length to obtain a snap-over effect on the contactaarm between the fixed con- 5 tact and the back stop; and means whereby the indicator moves the movable slide to make or break a circuit in which the contacts are included.

5. Temperature indicating and control mechanism comprising a thermostatically actuated indicator; a regulator movable relative to the indicator; circuit opening and closing means comprising a slide movable on the regulator and carrying a fixed contact and a back stop; a contact movable on the regulator by and between the fixed contact and the back stop; snap-over mechanism operative on the movable contact adapted when the movable contact is moved by the fixed contact to snap the movable contact into engagement with the back stop and vice versa; means 4 tending to move the slide in one direction to cause the movable contact to engage the fixed contact; and a projection movable by the indicator adapted to actuate the slide in the opposite direction to cause the movable contact to disengage the 4 fixed contact and engage the back stop.

6. Temperature indicating and control mechanism comprising a thermostatically actuated indicator; a regulator movable relative to the indicator; circuit opening and closing means comprising a slide guided on the regulator and movable relative thereto; a fixed contact carried by the slide; a contact carried by the regulator and movable relative thereto into and out of engagement with the fixed contact; and means operable 5 by the indicator for moving the slide to cause the movable contact to engage or disengage the fixed contact and thus make or break a circuit in which the contacts are included.

'7. Temperature indicating and control mechanism comprising a thermostatically actuated indicator; a regulator movable relative to the indicator; circuit opening and closing means comprising a slide movable on the regulator and carrying a fixed contact and a back stop spaced therefrom; a U-shaped spring frame carried by the regulator and having two arms; a contact arm;

a toggle member having one end pivotally engaging an end of the contact arm, the other end of the toggle member being pivoted on one arm 7 of the U-shaped frame, the contact arm being pivoted intermediate its ends on the other arm of the U-shaped frame, the free end of the contact arm being adapted to be moved by one of the fixed contact and back stop parts to cause 1 it to be snapped into engagement with the other of said parts when the pivotal connection between the contact arm and toggle member is moved past the line of center of the said pivotal connections with the arms of the U frame; and means operable by the indicator for moving the slide and thus the fixed contact and the back stop to actuate the contact arm.

8. Temperature indicating and control mechanism comprising a thermostatically actuated indicator; a regulator movable relative to the indicator; a circuit opening and closing means comprising a slide movable on the regulator and carrying a fixed contact and a back stop spaced therefrom; a contact movable on the regulator by and between the fixed contact and the back stop; snap-over mechanism for actuating the movable contact when the latter is moved by the fixed contact to cause the movable contact to snap into engagement with the back stop and vice versa; means tending to move the slide in one direction to cause the movable contact to engage the fixed contact; means for limiting the movements of the slide; an arm adapted to be moved by the indicator; a projection carried by the arm for moving the slide in the direction opposite that imparted thereto by the last mentioned means to cause the movable contact to disengage the fixed contact and engage the back stop; and a drive connection including a spring between the arm and the indicator for permitting the latter to overrun the arm when the projection has moved the slide to efiect the disengagement of the movable and fixed contacts.

9. Temperature indicating and control mechanism comprising a thermostatically actuated indicator; a regulator movable relative to the indicator; circuit opening and closing means comprising a slide guided on and movable relative to the regulator and carrying a fixed contact and a back stop spaced therefrom; a contact carried by the regulator and movable relative thereto by and between the fixed contact and the back stop; and means interposed between the indicator and the slide for actuating the latter to cause the movable contact to engage or disengage the fixed contact and thus make or break a circuit in which the contacts are included.

10. Temperature indicating and control mechanism comprising a thermostatically actuated indicator; a regulator movable relative to the indicator; circuit opening and closing means comprising a slide guided on and movable relative to the regulator and carrying a fixed contact and a back stop spaced therefrom; a contact carried by the regulator and movable relative thereto by and between the fixed contact and the back stop; and means interposed between the indicator and the slide for actuating the latter to cause the movable contact to engage or disengage the fixed contact and thus make or break a circuit in which the contacts are included; and means carried by the slide and regulator for limiting the movements in opposite directions of the slide, the slide actuating means including provisions for permitting the indicator to continue its movement independently of the slide after the circuit is broken.

FRANCIS A. HUTCHINSON. 

